Slush-pump piston



c 9 7 H. B. MOORE SLUSH PUMP PISTON Filed Dec. 18. 1924 V A 7" TOE/YE Y Patented Oct. 25, 1927.

"UNITED STATES 1,646,927 PATENT OFFICE.

HERBERT B. MOORE, OF LOS ANGELES, CALIFORNIA, ASSIG'NOR OF ONE-HALF TO ELDON L. FELTCH, 0 LOS ANGELES, CALIFORNIA.

SLUSH-I'UMP PISTON.

Application filed December 18, 1924. Serial No. 756,715.

My present invention relates to pistons especially suitable for use in slush pumps, or the like; and it is an especial object of this invention to provide a piston adapted -to operate efficiently and to resist wear even when used in the pumping of a liquid, such as the slush or mud which is commonly circulated through deep well drills, which circulating liquid often contains large quantities of sand or other gritty and abrasive materials.

Hydraulic pistons comprising rubber sleeves to the back of which pressure is alternately admitted from opposite directions are in current use. The rubber sleeves referred to are commonly disposed circumferentially of piston heads; and they may be retained between abody and a follower secured to a rod, both said body and said follower being apertured to admit fluid pressure back of said rubber sleeve. This may be provided with, for example, inwardly projecting flanges adapted to operate as valves; but it is an object of my invention to obviate the necessity for such valves and to provide a piston having a novel rubber sleeve so formed and retained, as by means of a. substantially central inwardly extending fin, that fluid pressure forces the respective peripheral edges of said sleeve alternately into a sand-excluding engagement with the walls of the cylinder within which my. piston may be reciprocated. The base or inner portion of the mentioned packing sleeve is preferably wider than the peripheral portion thereof; and the central or intermediate portion thereof is preferably restrained by a fin constituting a partition between two chambers and interfitted or gripped between said body and said follower.

It is an object of this invention to provide a piston or packing sleeve adapted to operate continuously for long periods of time,

" effectively resisting wear and gradually expanding in such manner as largely to compensate therefor.

It is an object of this invention to provide a piston packing sleeve whose peripheral edges, more than the central portion thereof, shall respond to internal fluid pressures applied first in one chamber and then within an adjacent chamber separated therefrom by a fin or median partition; and a preferred embodiment of my invention may comprise a piston sleeve having outwardly convergent conical or convex lateral surfaces and adapted to respond to outward pressure by a sllding movement thereof relatively to interfitting surfaces formed respectively on a piston body and a follower. Said body and said follower may also be provided with opposable surfaces havino annular channels which co-operate to define a groove into which the mentioned fin on said packing ring may extend; and this extension may be such as to serve not only for the exclusion of sand from entrance between said body and said follower, but also to permit a suitably restrained outward movement of the central portion of said packing sleeve, to compensate for wear therein. 1

' It is a further object of my invention to provide a packing sleeve having outwardly convergent lateral surfaces, these surfaces being preferably harder than the main portion of said sleeve and capable of a sliding movement relatively to metallic surfaces of a body and a follower interfitting therewith, the central portion of the mentioned sleeve being at all times restrained, substantially as described.

Other objects of my invention will appear from the following description of an illustrative embodiment thereof, taken in con nection with the appended claims and the accompanying drawings, in which Fig. 1 is a substantially median section through a piston embodying my invention.

Fig. 2 is a transverse sectional view on a reduced scale, taken substantially as indicated by the line 2-2 of Fig. 1.

Fig. 3 is also a transverse sectional view, this View being on substantially the same scale as Fig. 2, and taken as if on the line Referring to the details of that specific embodiment of my invention chosen for purposes of illustration, 11 may be a piston body, and 12 may be a co-operating follower, these elements being shown as held on a piston rod 13 by means of a nut 14 and a lock nut 15,

sion of fluid pressure, but with outwardly convergent opposite conical or other concave surfaces 19 and 20, adapted to co-operate with correspondingly inclined,surfaces21 and 22 of a one-piece packing sleeve 23; and

this packing sleeve may be provided with a substantially central inwardly projecting fin or web 24, shown as seated within a-g'roove or channel 25. Instead. of cutting this channel 25 entirely from either the head 11 or the follower 12, I showthe same'as formed the cutting of separate grooves or channels in these respective elements insuchmanner that the outwardly convergent-faces26 and 27 thereof serve as a means of engaging the fin 24:, and thereby restraining the central region of the described packing sleeve against outward movement, in response to'fluid pressure.

i The lateral surfaces21 and 22 'of the sleeve 23 may be harder than the main body thereof, and maybe adaptedto "slide relatively to the surfaces 19 and 20, in response to fluid pressure, or-in compensation for wear; and it will be obvious thatfluid pressure applied alternately Within the annular chambers 28 and 2.9,"communicating respectively with the passages 17 and 18,-may thus beeifective to force the peripheral edges 30 and 31 alternately outward, this outward pressure upon one of these edges 'being greatest when thepressure upon the other is least, and the maximum pressure being applied to that edge which is, at any given time, the leading edge,'-or the edge at that side of the piston which is advancing in opposition to ahigh pressure. I

If the sleeve 23 is formed, except as indicated, of a'comparatively soft rubber composition, and when the piston is moving in the direction of the arrow 32, *for example, high pressure fluid then entering in the direction of the arrows 33, 33, this application of pressure within the chamber 28, may, for example, force the inner surface of said chamber into the position indicated bythe dotted'lines 3 1-, 34'. As a result, the peripheraledge 3O may be pressed outwardly, substantially as indicated in-an exaggerated manner by the dotted lines 35,35, the centralregion 36 being restrained inthe mannerdescribed, and the peripheral edge 31 being under a reduced pressure permitting the same to move slightly inward. It will be obvious that these movements and relationships are favorable to the exclusion of sand and to the avoidance of undue wear,

and that even when the outer portion of my novel packing sleeve is worn away, the fin 24: being gradually drawn outward within the channel 25, the inward expansion of the saidfin, or its equivalent, may nevertheless continue effective to prevent entrance of sand between the body 11 and the follower in compensation for wear, until its thickness shall be greatly reduced. The'presenceof theintermediate fin or web 24, and thecomparative freedom of movement of the reispectiveaedgcs 30 and 31, obviate the necessit for an, use of elements 0 eratin as valves, and-operate also to assure the main tenance of a tight fit exactly where such a fit is ofthe greatest practicalimportance, and to reduce friction. i r Although I have herein described my invention in a preferred form, I am aware that various changes and modifications may be made by those skilled in the art to which this case relates, without; the slightest departure from the spirit and scope of my invention, as the same is indicated above and in the following claims,

I claim as my invention: 7

' 1. A pump piston comprising a body; a follower; and a'single packing sleeve therebetweenprovided withoutwardly convergent lateral surfaces and with means for admitting fluid pi'essure'alternately beneath the respective' peripheral-edges thereof one at a time.

2. A pump piston comprising a body; a

follower; anda single Packing sleeve therebetween provided with outwardly convergent lateral surfaces and with means for admitting fiuidpressure alternately beneath the respective peripheraledgesthereof one at a time, said head and said follower being provided with inner surfaces interfitting with said lateral surfaces'of said packing sleeve. pump piston comprising a body; a follower; and a packing sleeve therebetween provided with outwardly convergent lateral surfaces and with means for, admitting fluid pressure alternately beneath the respective peripheral edges thereof, said sleeve being provided with means for restraining the outward JIIOVGIDGIlt of an intermediate pe ripheral region thereof.

4. A pump piston comprising a body; a follower; and a packing sleeve therebetween provided with outwardly convergent lateral surfaces and with means for. admitting fluid pressure alternately beneath the respective peripheral edges thereof, said sleeve being formed of a restraining means serving also with means engaging the inner portion of said restraining and partitioning means.

6. A pump piston comprising: a single inwardly expanding packing sleeve; a body; and a follower, each of the latter being provided with a concave interior surface adapted slidably to engage a lateral surface of said inwardly expanded packing sleeve, and each provided with a pair of inwardly expanding channels for the reception of a substantially central fin extending from said sleeve.

7. A piston comprising a packing element provided with a substantially central interior means for restraining outward mvement of the central region thereof, and with lateral surfaces artificially hardened.

8. A piston comprising a packing element provided with a substantially central interior means for restraining outward movement of the central region thereof, and with outwardly convergent lateral surfaces.

9. A piston comprising a packing sleeve having hardened lateral surfaces outwardly convergent and a. comparatively elastic interior.

10. A piston packing sleeve formed in one piece. and having hardened lateral surfaces outwardly convergent and a comparatively elastic interior.

11. A piston packing sleeve as defined in claim 10, having an inwardly expanded central retaining fin.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this th day of December, 1924.

HERBERT B. MOORE. 

